Cannula with floating clamping member

ABSTRACT

A cannula has a longitudinal base member having a first clamping end and a longitudinal arm member pivotally attached to the longitudinal base member and having a second clamping end, the cannula being in a closed position when the first and second clamping ends are brought together. A first clamp member is located at the first clamping end and has a first passage. A second clamp member is rotatably attached to the arm member at the second clamping end and has a second passage. The first and second passages form a combined passage when the clamp is in the closed position. The cannula may have a first locking member positioned on the arm member and a second locking member positioned on the base member. The first and second locking members interact with each other to lock the cannula in the closed position.

RELATED APPLICATION

This application is a Divisional of U.S. Pat. No. 8,814,889, filed Jul.10, 2012. This disclosure of this prior patent is herein incorporated byreference.

BACKGROUND

Related technical fields include cannulas and clamping methods includingcannulas and clamping methods for perfusing one or more organs or tissueto monitor, treat, sustain and/or restore the viability of the organ(s)or tissue and/or for transporting and/or storing the organ(s) or tissue.

Various devices have been developed that couple the anatomy of an organbeing perfused to a perfusion machine or other equipment such as thatdescribed in U.S. Pat. No. 7,824,848, the entire disclosure of which ishereby incorporated by reference. Such devices are typically referred toas perfusion clamps or simply cannulas. Although the term cannula ingeneral use has other meanings, the term cannula is used genericallythroughout this specification to refer to a clamp or other device thatprovides a connection through which fluid flow may be established.

A type of cannula as described in U.S. Pat. No. 5,728,115 to Westcott etal. is shown in FIGS. 1-3. A clamping device (cannula) 10 is used tocouple a perfusion device to the renal aorta 34. The clamp 10 includestwo longitudinal members 12 and 14 which pivot about a pin 16. Theproximal end of the member 12 includes an integral handle 18, while theproximal end of the member 14 includes an integral handle 20. The distalend of the member 12 includes an elongated, hollow, annular, integralclamp head 24, while the distal end of the member 14 includes anelongated, hollow, annular, integral clamp head 26. Clamp head 26includes a nipple 28 attached thereto. Movement of the handles 18 and 20toward one another forces the members 12 and 14 to pivot about the pin16, thereby forcing the clamp heads 24 and 26 of the members 12 and 14away from one another. A spring 22 is positioned between the handles 18and 20 in order to bias the handles apart. This, in turn, tends to forcethe clamp heads 24 and 26 together. Therefore, the clamp heads 24 and 26of the distal ends of the members 12 and 14 are engaged in a clampingrelationship unless an external compressive force is applied to thehandles 18 and 20. A lumen 32 extends through the nipple 28.

In use, the clamp 10 is attached to a blood vessel of a donor organ suchas the renal aorta 34 of a kidney 36 by opening the clamp 10, passingthe distal end 38 of the renal aorta 34 through the annular clamp head24, holding the distal end 38 of the renal aorta 34 over the annularclamp head 24, and releasing pressure on the handles of the clamp 10 inorder to allow the clamp head 26 to engage the distal end 38 of therenal aorta 34 against the annular clamp head 24. A catheter 40 may thenbe attached to the nipple 28 in order to provide perfusion of liquidthrough the lumen 32 and into the renal aorta 34.

SUMMARY

In the cannula described above, the orientation of the clamp heads 24and 26 with respect to each other is fixed because the clamp heads 24and 26 are integral to the members 12 and 14, respectively. Accordingly,the force applied to the tissue during the clamping process may beunevenly distributed across the surface of the tissue, therebypotentially resulting in damage to the tissue or an inadequate grip thatis susceptible to failure. In addition, although the cannula shown inFIGS. 1-3 is biased in the closed or clamping position by the spring 22,the cannula does not include a locking mechanism to prevent the cannulafrom opening at an undesired time. Also, the cannula shown in FIGS. 1-3provides poor visibility of the vasculature because of a limited rangeof movement and because the clamp heads 24 and 26 are made of an opaquematerial (typically metal). The limited range of movement also limitsaccess to the clamp heads 24 and 26, increasing difficulty of use.Further, the nipple 28 may be susceptible to leaks due to a relativelysmooth construction and the spring 22 does not allow for adjustment ofthe force applied to clamped tissue.

In exemplary embodiments, a clamp such as a cannula includes alongitudinal base member and a longitudinal arm member pivotallyattached to the longitudinal base member. The clamp also includes afirst clamp member at a first end of the base member and a second clampmember pivotally attached to the arm member at a first end of the armmember, the first clamp member opposing the second clamp member. Thesecond clamp member may be movable in more rotational axes and/or morerotational directions with respect to the arm member than the arm memberis movable with respect to the base member. In addition, the secondclamp member may have one or more than one degree of freedom of movementrelative to the arm member, for example, two rotatable degrees offreedom with respect to the arm member.

Pivotally attaching the second clamp member to the arm member allows forforce applied to the tissue during the clamping process to be moreevenly distributed, thereby reducing damage to the tissue. In addition,the grip on the tissue may be less likely to fail. Also, pivotallyattaching the second clamp member to the arm member may allow the afirst clamping surface to have a variable position relative to a secondclamping surface when the arm member and the base member are held inplace with respect to one another.

In exemplary embodiments, a clamp such as a cannula includes alongitudinal base member having a first clamping end and a longitudinalarm member pivotally attached to the longitudinal base member and havinga second clamping end. The clamp is in a closed position when the firstand second clamping ends are brought together. The clamp also includes afirst locking member positioned on the arm member and a second lockingmember positioned on the base member. The first and second lockingmembers interact with each other to releasably lock the clamp in theclosed position.

In exemplary embodiments, a clamp such as a cannula includes alongitudinal base member having a first clamping end and a longitudinalarm member pivotally attached to the longitudinal base member and havinga second clamping end, the clamp being in a closed position when thefirst and second clamping ends are brought together. The clamp alsoincludes a first clamp member at a first end of the base member and asecond clamp member movably (e.g., pivotally) attached to the arm memberat a first end of the arm member, the first end of the arm memberopposing the first end of the base member. In addition, the clampincludes a first locking member positioned on the arm member and asecond locking member positioned on the base member. The first andsecond locking members interact with each other to releasably lock theclamp in the closed position.

In exemplary embodiments, a method of clamping or cannulating a bloodvessel includes clamping the blood vessel between a first clamp surfacethat applies a first force on the blood vessel and a second clampsurface that applies a second force on the blood vessel. A magnitude ofthe first force is substantially consistent over an entire surface ofthe blood vessel that is in contact with the first and second clampsurfaces. Clamping or cannulating the blood vessel may facilitate aconnection between the blood vessel and a perfusion apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary implementations can be described with reference to thefollowing figures wherein:

FIGS. 1-3 illustrate a cannula of the prior art;

FIG. 4 illustrates an exemplary clamping apparatus in a closed position;

FIG. 5 illustrates an exemplary clamping apparatus of FIG. 4 in an openposition;

FIG. 6 illustrates an exemplary base member of the clamping apparatus ofFIGS. 4 and 5;

FIG. 7A illustrates an exemplary floating clamp member of the clampingapparatus of FIGS. 4 and 5;

FIG. 7B illustrates another view of the floating clamp member of FIG.7A;

FIG. 8 illustrates an exemplary floating clamp member seat of theclamping apparatus of FIGS. 4 and 5; and

FIG. 9 illustrates exemplary clamping surfaces of the clamping apparatusof FIGS. 4 and 5.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 4 shows a perfusion clamping apparatus or cannula 100 according toexemplary embodiments. The cannula 100 is capable of connecting one ormore blood vessels of an organ or tissue to a perfusion machine orsystem (not shown) such as that described in U.S. Pat. No. 7,824,848,the entire disclosure of which is hereby incorporated by reference, forexample, by connection to tubing of the perfusion machine or system. Allmedical fluid contact surfaces are preferably formed of or coated withmaterials compatible with the medical fluid used, preferablynon-thrombogenic materials. For convenience, the term “organ” will beused herein to mean organ and/or tissue, except as otherwise specified.

The medical fluid for perfusion may be any suitable medical fluid. Forexample, it may be a simple crystalloid solution, or may be augmentedwith an appropriate oxygen carrier. The oxygen carrier may, for example,be washed, stabilized red blood cells, cross-linked hemoglobin,pegolated hemoglobin or fluorocarbon based emulsions. The medical fluidmay also contain antioxidants known to reduce peroxidation or freeradical damage on the physiological environment and specific agentsknown to aid in tissue protection. Further, the medical fluid may be orinclude blood or blood products.

The cannula 100 is shown in FIG. 4 in a closed or clamping condition andin FIG. 5 in an open condition. The cannula 100 may comprise a base 102,an arm 104, an optional locking mechanism 106 and a floating clampmember 108. Although the floating clamp member 108 is illustrated asbeing attached to the arm 104, it is contemplated that the floatingclamp member 108 may be attached to the base 102 instead of the arm 104.It is further contemplated that the base 102 and the arm 104 may both beattached to respective floating clamp members 108. The base 102 and thearm 104 may be pivotably connected via a pivot mechanism 110. Asillustrated, the pivot mechanism 110 may be a pin about which one orboth of the base 102 and the arm 104 can rotate. The pivot mechanism 110may be positioned at any location between a distal end 112 and aclamping end 114 of the cannula 100. As can be seen in FIG. 4, when thecannula 100 is in the closed condition, the base 102 and the arm 104 arebrought together at the distal end 112 and at the clamping end 114. Ascan be seen in FIG. 5, when the cannula 100 is in the open condition,the base 102 and the arm 104 are moved apart from each other at thedistal end 112 and at the clamping end 114. When being rotated from theclosed condition to the open condition, the arm 104 and/or base 102 maybe rotated as much as or more than 180 degrees.

The base 102 and the arm 104 may be pivotable around an axis 116 of thepivot mechanism 110 that extends in a first direction and may beadjacent to each other at the pivot mechanism 110 in the firstdirection. The first direction may be perpendicular to a longitudinalaxis of the cannula 100. The base 102 and the arm 104 may also beadjacent to each other in the first direction at the distal end 112 butmay be adjacent to each other in a second direction at the clamping end114. The second direction may be different from the first direction. Thesecond direction is preferably, but not necessarily, substantiallyperpendicular to the first direction. For example, FIG. 4 illustratesthe base 102 and the arm 104 as being adjacent to each other at thepivot mechanism 110 in a side-by-side configuration (i.e., adjacent inthe first direction). FIG. 4 also illustrates the base 102 and the arm104 as being overlapped at the clamping end 114 in a stackedconfiguration (i.e., overlapped in the second direction). The base 102and the arm 104 are preferably pivotable with respect to each otheraround only the axis 116.

As illustrated in FIGS. 4 and 5, there is preferably no biasing member(such as the spring 22 shown in FIG. 1) that biases the cannula 100towards either a closed or open position. Such a lack of a biasingmember may be advantageous in that the cannula 100 can be opened orclosed, or adjusted to any position in between, and remain in thatposition without further action by a user. If such a biasing member wereincluded, further structure, such as a brake or locking mechanism, couldbe included to achieve the advantage of the cannula 100 remaining in aposition set by the user (other than the position dictated by thebiasing member). A lack of biasing member may also allow the cannula 100to open wider than if a biasing member is provided. For example, thespring 22 shown in FIG. 1 requires that the cannula 10 be squeezed toopen, and there is limited travel between the handles 18 and 20, whichresults in a limited opening space between clamp heads 24 and 26.However, the cannula 100 shown in FIGS. 4-5 is not so limited. Thecannula 100 has a squeeze-to-close action opposite of thesqueeze-to-open action of the cannula 10. By including asqueeze-to-close action and no biasing member, the cannula 100 can beopened over a much wider range than is possible with the cannula 10 ofFIG. 1. Also, such a squeeze-to-close configuration without a biasingmember may allow for intermediate positions or stop points between afully open position and a fully closed position. Any desired stop pointsmay be provided with structure than tends to keep the cannula 100 in anintermediate position. Such structure could be achieved, for example,using detents (not shown). However, one of ordinary skill wouldappreciate that the cannula 100 could include a biasing member biasingthe cannula 100 either open or closed if the needs of a user so dictate.

The base member 102 may include a first gripping portion 118 and aclamping portion 120. The first gripping portion 118 may extend from thedistal end 112 of the cannula 100 to near the clamping members, e.g.,the optional locking mechanism 106, and may be ergonomically configuredto receive at least a first portion of a right and/or left hand of auser. The clamping portion 120 may be integrally formed with the basemember 102 or may be a separately formed component. In addition, theclamping portion 120 may include an opening 122 through which an aorticpatch or other type of vasculature of an organ may be fed. The clampingportion 120 may also include a first clamping surface 124 that isconfigured to cooperate with the floating clamp member 108 to clamp theaortic patch or other type of vasculature of the organ.

The arm member 104 may include a second gripping portion 126 and afloating clamp member seat 128. The second gripping portion 126 mayextend from the distal end 112 of the cannula 100 to near the clampingmembers, e.g., the optional locking mechanism 106, and may beergonomically configured to receive at least a second portion of theright and/or left hand of the user. The floating clamp member seat 128may be configured to receive and support the floating clamp member 108.

The cannula 100 may preferably be configured to be operated (i.e., movedfrom the open condition to the closed condition or moved from the closedcondition to the open condition) by one hand of the user. In addition,the cannula 100 may be ergonomically configured to be used by either aleft hand or a right hand of the user. For example, in a left-handedconfiguration (as shown throughout the figures), the base 102 may bepositioned to the right of the arm 104 at the pivot mechanism 110 whenthe cannula 100 is oriented so that the clamping end 114 is furthestfrom the user. Conversely, in a right-handed configuration (amirror-image of what is shown throughout the figures), the base 102 maybe positioned to the left of the arm 104 at the pivot mechanism 110 whenthe cannula 100 is oriented so that the clamping end 114 is furthestfrom the user.

The optional locking member 106 may lock the cannula 100 in the closedcondition. Preferred embodiments may include a primary lock member 130,a toothed member 132 and an optional secondary lock member 134. Theprimary lock member 130 may be pivotally connected to the base 102 andmay include an interacting portion 136, an unlocking portion 138 and abiasing portion 140. The interacting portion 136 may extend from thebase 102 toward the toothed member 132 attached to the arm 104 and maypivot between a locked position and an unlocked position. Theinteracting portion 136 may include a hook-like portion 142 that may bepositioned between the teeth of the toothed member 132. When thehook-like portion 142 is hooked to a tooth of the toothed member 132,the locking member 106 prevents the arm 104 from rotating open withrespect to the base 102. It is contemplated that the toothed member 132may be flexibly or pivotally attached to the arm 104. In either case,the toothed member 132 may be optionally biased. It is furthercontemplated that the primary lock member 130 may be pivotally connectedto the arm 104 and the toothed member 132 may be flexibly or pivotallyattached to the base 102.

The unlocking portion 138 may be connected to the interacting portion136 at a pivot 144 so that when the unlocking portion 138 is pivotedaround the pivot 144, the interacting portion is also pivoted around thepivot. The unlocking portion 138 is preferably positioned so that thebase 102 is between the unlocking portion 138 and the interactingportion 136. Accordingly, pressing the unlocking portion 138 toward thebase member 102 may cause the interacting portion 136 to move into theunlocked position. Conversely, allowing the unlocking portion 138 topivot away from the base member 102 may cause the interacting portion136 to move into the locked position.

The biasing member 140 is optional, and may be a spring-like elementthat extends from the interacting portion 136 toward the base 102. Thebiasing member may apply a biasing force that biases the interactingportion 136 toward the locked position.

The optional secondary lock member 134 may include a first slidingmember 146 (as illustrated in FIG. 4) and a second sliding member 148(as illustrated in FIG. 6). The first sliding member 146 may bepositioned on the same side of the base 102 as the interacting portion136. Positioning the first sliding member 146 in this manner may allowthe optional secondary lock member 134 to be actuated by the user'sthumb. The first sliding member 146 may be slidable toward and away fromthe interacting portion 136. The second sliding member 148 may bepositioned on the same side of the base 102 as the unlocking portion 138and may be slidable toward and away from the unlocking portion 138. Thefirst and second sliding members 146 and 148 are connected to each otherso that when the first sliding member 146 is moved in a particulardirection, the second sliding member 148 is moved in the same direction.In addition, the second sliding member 148 is positioned so that whenthe second sliding member 148 is moved toward the unlocking portion 138,the second sliding member 148 is moved between the base 102 and theunlocking portion 138. This has the effect of preventing the unlockingportion 138 from being pressed toward the base 102. Accordingly, whilethe second sliding member 148 is between the unlocking portion 138 andthe base 102, the interacting portion 136 cannot be moved to theunlocked position, and the cannula 100 cannot be moved from the closedcondition to the open condition. This is advantageous because thecannula 100 is less likely to open unintentionally, which could resultin the loss of or damage to an organ that has been cannulated.

The first sliding member 146 may be omitted from the secondary lockmember 134. In an embodiment without the first sliding member 146, theuser may operate the optional secondary lock member 134 by sliding thesecond sliding member 148, which may be accomplished with one of theuser's fingers.

As illustrated in FIGS. 7A and 7B the floating clamp member 108 mayinclude a coupling portion 150, a support portion 152 and a cup portion154. The coupling portion 150 may form a tubular structure and mayprovide a connection (such as a hose barb or luer lock) to a tube orother fluid conduit that connects the cannula 100 to the perfusionmachine or system (not shown). Use of a hose barb or luer lock isadvantageous because such structures are less likely to leak than thenipple 28 shown in FIGS. 1-3.

In embodiments, the cannula 100 may include features that allow for thesecond clamping surface 178 to change an angle relative to the firstclamping surface 124 other than through movement of the base 102 and thearm 104. The change in relative angle can be about one or more axes.Such a change in angle can allow for the cannula 100 to clamp orcannulate varying thickness of tissue in a single blood vessel or thelike that would otherwise prove troublesome with a cannula that does notallow for similar relative changes in angle between clamping surfaces.For example, with a cannula that does not allow for relative change inangle between clamping surfaces, it may be necessary to overly compress,and possibly damage, a blood vessel that is being cannulated or clampedin order to produce an adequate seal. Alternatively, a seal that leaksmay be required in order to avoid damage to the blood vessel.

In the depicted embodiment, the support portion 152 may include aplurality of features to connect the floating clamp member 108 to thearm 104. For example, the support portion may include a main body 156,upper primary support members 158, lower primary support members 160 andsecondary support members 162. The upper primary support members 158 maybe projections from the main body 156 and may each have a substantiallyhorizontal bottom surface 164. The lower primary support members 160 maybe positioned closer to the cup portion 154 than the upper primarysupport members 156 and may also be projections from the main body 156.The lower primary support members 160 may each have substantiallyhorizontal top surfaces 166. The secondary support members 162 may bepositioned closer to the cup portion 154 than the lower primary supportmembers 160 and may also be projections from the main body 156.Alternatively, the lower primary support members 160 may be positionedcloser to the cup portion 154 than the secondary support members 162.Either of these offset configurations may be advantageous in that wheninteracting with corresponding mating structure on the floating clampmember seat 128, two rotational degrees of freedom can be achieved whilepreventing a third rotational degree of freedom. The secondary supportmembers 162 may each have horizontal top surfaces 168. The upper primarysupport members 158 may preferably be on opposite sides of the main body156 from each other, the lower primary support members 160 maypreferably be on opposite sides of the main body 156 from each otherand/or the secondary support members 162 may preferably be on oppositesides of the main body 156 from each other. The upper primary supportmembers 158 and the lower primary support members 160 may have similaror different shapes and sizes.

As can be seen in FIG. 8, the floating clamp member seat 128 may includean opening 170 through which the floating clamp member 108 may beinserted and a support portion 172 surrounding the opening 170 that maysupport the floating clamp member 108. The support portion 172 mayinclude a plurality of first recesses 174 and a plurality of secondrecesses 176. The first recesses 174 may each be configured to receive acorresponding upper primary support member 158. In addition, each firstrecess 174 may be shaped complementarily to the corresponding upperprimary support member 158. For example, each of the first recesses 174may be closed at the bottom and may be open at the top. The firstrecesses 174 may be sized to have a larger volume than the respectivecorresponding upper primary support members 158 so that the upperprimary support members 158 may be free to move within the respectivecorresponding first recesses 174.

The second recesses 176 may each be configured to receive acorresponding lower primary support member 160. In addition, each secondrecess 176 may be shaped complementarily to the corresponding lowerprimary support member 160. For example, each of the second recesses 176may be open at the bottom and may be closed at the top. The secondrecesses 176 may be sized to have a larger volume than the respectivecorresponding lower primary support members 160 so that the lowerprimary support members 160 may be free to move within the respectivecorresponding second recesses 176.

The configuration of the support portion 172 within the floating clampmember seat 128 may permit the floating clamp member 108 to rotatearound more than one axis. For example, the floating clamp member 108may rotate around an axis 180 that extends through centers of the upperprimary support members 158. The axis 180 may extend along a plane thatis parallel to a longitudinal axial plane of the cannula 100. Thefloating clamp member 108 may also rotate around an axis 182 thatextends through centers of the lower primary support members 160. Theaxis 182 may also extend along a plane that is parallel to thelongitudinal axial plane of the clamping apparatus. Other structuresthat allow at least two degrees of rotation between the floating clampmember 108 and the arm 104 are contemplated by the inventive principlesdiscussed herein.

By permitting the floating clamp member 108 to rotate around two or moredifferent axes, the orientation of a second clamping surface 178 may bevariable with respect to the orientation of the first clamping surface124. Accordingly, the cannula 100 may be more sensitive to variations inthickness of the tissue being clamped, thereby reducing the amount ofdamage to the tissue that may occur during the clamping process andreducing the likelihood that the grip will fail. Such rotation about twoor more different axes also allows the first clamping surface 124 andthe second clamping surface 178 to approach and/or engage one another,or engage clamped tissue, in a parallel fashion. In this mariner, theentirety of each clamping surfaces will engage as near to simultaneouslyas practicable, which may result in more even application of clampingforce and less likelihood of damage (or uneven damage) to clampedtissue. Evenly distributed clamping force may also be achieved, whichmay result in a superior seal versus clamping surfaces that cannotachieve such relative movement. Preferably, the floating clamp member108 has a range of motion about each axis of about 15 degrees (7.5degrees of positive and negative rotation for each axis) and morepreferably about 12 degrees (6 degrees of positive and negative rotationfor each axis) to avoid superfluous movement.

The cup portion 154 of the floating clamp member 108 may include thesecond clamping surface 178, which interacts with the first clampingsurface 124 of the base 102 to clamp the tissue. As can be seen in FIG.9, one clamping surface (e.g., the second clamping surface 178) may havea larger diameter than the other clamping surface (e.g., the firstclamping surface 124). Although FIG. 9 illustrates the second clampingsurface 178 having a larger diameter than the first clamping surface124, it is contemplated that the first clamping surface 124 can have thelarger diameter. In addition, one clamping surface may have a steppedshape along a perimeter, while the other clamping surface may have ashape complementary to the stepped shape of the one clamping surface inorder to form a tighter seal around the clamped tissue. Alternatively,the first clamping surface 124 and the second clamping surface 178 mayhave similar cross-sectional shapes. It should be understood that, whilein the closed position, the clamping surfaces can be in contact witheach other or spaced apart a suitable distance (e.g., 0.5 mm to 4.00 mm,more preferably 1.0 mm to 3.0 mm) to accommodate tissue.

The cannula 100 can be made from any suitable material or materials,such as metal or transparent or opaque plastics, but plastics provideseveral advantages. Plastics are usually less costly, and can thereforebe made disposable. A disposable version of the cannula 100 will nothave the additional costs associated with reuse, such asre-sterilization.

Portions of the cannula 100 can be made from optically transparentmaterial. This may be beneficial in that it can aid a clinician inpositioning the vasculature and in detecting air bubbles or the interioror intima of the vasculature.

Either or both of the first clamping surface 124 and the second clampingsurface 178 can include serrations and/or knurls to facilitate securingthe clamped tissue. If the serrations or knurls are made from plastics,the plastics can be chosen with specific material properties to limit orprevent damage to clamped tissue. Additionally, serrations or knurls canbe specifically tailored to the tissue to be clamped. The first clampingsurface 124 and/or the second clamping surface 178 may include anelastomeric material to work in conjunction with and/or be substitutedfor the serrations and/or knurls.

While various features have been described in conjunction with theexamples outlined above, various alternatives, modifications,variations, and/or improvements of those features and/or examples may bepossible. Accordingly, the examples, as set forth above, are intended tobe illustrative. Various changes may be made without departing from thebroad spirit and scope of the underlying inventive principles.

What is claimed is:
 1. A method of cannulating a blood vesselcomprising: inserting the blood vessel through an opening within a firstclamp member; and clamping a portion of the blood vessel between a firstclamp surface of the first clamp member and a second clamp surface of asecond clamp member, wherein: the first clamp surface applies a firstforce on the clamped portion of the blood vessel, the second clampsurface applies a second force on the clamped portion of the bloodvessel, and the second clamp surface is configured to pivot relative tothe first clamp surface such that a direction in which the second forceis applied to the clamped portion of the blood vessel is able to changerelative to a direction in which the first force is applied to theclamped portion of the blood vessel and that both the first clampsurface and the second clamp surface are configured to contact the bloodvessel along each of their entire lengths when the second clamp surfaceis pivoted relative to the first clamp surface.
 2. The method of claim1, further comprising: moving a distal end of an arm member attached tothe first clamp surface and a distal end of a base member attached tothe second clamp surface toward each other to apply the first and secondforces, the distal end of the arm member and the distal end of the basemember being distal to the blood vessel.
 3. The method of claim 2,wherein the first force and the second force are applied in opposingdirections.
 4. The method of claim 1, wherein an orientation of thesecond clamping surface is dependent on the shape of the surface of theclamped portion of the blood vessel.
 5. The method of claim 4, whereinan orientation of the first clamping surface is independent of the shapeof the surface of the clamped portion of the blood vessel.
 6. The methodof claim 1, further comprising locking the first and second clampmembers in a clamping position in which the portion of the blood vesselis clamped between the first clamp surface and the second clamp surface.7. The method of claim 6, wherein the first clamp member is attached toa base member and the second clamp member is attached to an arm member.8. The method of claim 7, further comprising locking the arm and basemembers in the clamping position by pivoting one locking member to alocking position in which the one locking member interacts with anotherlocking member.
 9. The method of claim 1, further comprising making afluid connection between the portion of the blood vessel and a perfusionapparatus by way of a fluid passage in the second clamp member.